Catalytic isomerization process



Jan. 8, 1946. w. o. WEBBER 2,392,791

CATALYTIC IS'OMERIZATION. PROCESS I Y Filed Noy. 25, 1945 '1 A 4- w 17 IO [6 ll 15 4- Absorber Reuc'lor Stripper 3 I .1 r I 3 I I 2. y i I X 1 l k. i l l3 l i '5 I I I I 1 I l I I 4 I4 I I l g I i l 1 I 6 l I I I I I I I i x l0 L L I I -1 4 I "r" H 8 I 1 r 1 \H 1 1 l8 v 5 r Absorber Zone Reactor Zon M 02 w/lNVENToR.

p0? Wm ATTORNEY.

Patented Jan. 8, 1946 r 2,392,191 CATALYTIC rsomimzl 'rron raocnss William 0. Webber, Baytown, Tex., assignor Standard Oil Development Company, a corporation of Delaware Application November 25, 1943, Serial No. 511,721

' 2 Claims. (01. zoo-683.5)

The present invention is dir'ectedtoa method and apparatus for carrying out reactions involving liquids and gases.

There are many reactions, inwhich a liquid is either reacted with a gas or'reacted-in the presence of a gas promoter, in which difllculty is encountered by reason oi. the carrying of! of the gas by the liquid product. It is to the prevention of such loss of gaseous reagent or promoter or, in the alternative, the avoidance of expensive auxiliary equipment that the present invention is directed. A typical process to which the present invention is applicable is the isomerization of normal parafllns to iso-parafllns in the presence of aluminum chloride and gaseous hydrogen chloride. The usual steps of this isomerization process consists of (1) mixing the normal parafiln with hysorptive support carrying aluminum chloride. Aheadof reaction vessel I is a tower 2, which maybe provided with bell cap plates or packed drogen chloride, (2) contacting this mixture, in v whichithe H01 acts as a promoter, with AlCla or other suitable catalyst at a suitable temperature and pressure, and (3) separating the hydrocarbon-HCl mixture leaving the reactor into gaseous HCl to be recycled back to the reactor and an ise-normal parailln mixture which is subjected fractionation.

Accm'dmg t0 the Present invention processes or the aforesaid type are carried out with a mini-' mum oi apparatus and a-niinlmum of, expensive bottom of tower 2 to the top of reaction vessel I r) while'this liquid in turn at a reduced temperature is contacted with the eilluent gas from'the reaction zone to absorb therefrom the more soluble gas and return it to the reaction zone.

The nature of the present invention may be better understood from the following detailed de-, scription of the accompanying drawing in which Fig. l is a front elevation in diagrammatic form of one type of apparatus suitable for the practice thereof, and

Fig. 2 is a vertical section of an alternative embodiinent. 7 V Referring to Fig. 1 in detail, numeral'i designates the reaction chamber, which, in a specific type 01' isomerization,'will be packed with an adwith contact material such as ceramic rings or balls; Assuming this apparatus to be used for the isomerization of butane in the liquid phase, the liquid butane is introduced into the top of tower 2 by way of line 3 and is conveyed from the byline 4. The reaction mixture leaves the bottom of vessel I through line 5, in which is arof a third tower I provided, similarly to tower gas losses by adopting a flow plan'wliich takes advantage of the change in'solubility 'ot the gas in the liquid with temperature. Briefly, in the process of the present invention areaction zonels established into the bottom'oi' which is'ied; the gas while the liquid. is introduced at the top. The gas issuing from the top oi. the reactor is passed countercurrent to'the liquid feed at a temperature suitable tor-absorption oi the 'gasin the I liquid. The liquid reaction product leaving the reactor is subjected to a temperature at which the solubility of the gas in the liquid is at a minimum and the gas so evolved is fed to the reaction ,zone. In the prefer-ed embodiment of this invention use is made of an extraneous stripper gas so .as to reduce the temperature to which the liquid reaction product mustbe heated in 'order'to liber ate the expensive reaction or promoting gas;

ranged a heater 6, and is discharged into the top z, with internal contact equipment; HClisint-roduced into through line 8.

In operating with this apparatus a sufilciently Gaseous the bottom of reactor l I high pressure is maintained in each 0!. the vessels 7, to keep the hydrocarbonsv in theJiquid phase.

Tower 2 is maintained at a relatively low temperature suitable for maximum solubility of hydrogen chloride in butane. tained at a'temperature suitable for the isomerization of butane in the presence otaluminum chloride. To adjust this temperature, if need be, a heater 9 is provided in line 4. Tower l is maintained at the temperature of minimum solubility 'of HCl in butane. v

The hydrogen chloride leaves reactor I through lin Ill, which feeds it into the bottom or tower 2. j Hydrogen chloride liberated in tower i is con- The method is applicable also to reactions. be-

tween gases wherein, according to the present invention, a liquid is employed in which one of the reacting gases is less soluble than the other. The more soluble gas is fed to the reaction zone while the less soluble gas is introduced countercurrent to the liquid product from ducted-by line H to inlet line" 8 Thus if; Will be seen that a maximum concentration of hydrogen chloride is maintained in the reaction vessel. In order to insure the maintenance-of proper temperatures in tower 2 and vessel I, coolers l2 and 13 are providedin lines H and I0, respectively. Line II isprovided witha check valv M.

In the preferred embodiment a stripper gas the reaction zone in a stripping relation thereto, such as hydrogen, methane, 00;, nitrogen. or

Vesseli is main- I .asoa'ra v the like,- is employed. This gas ismaintained in p a closed cycle represented by line l5 connecting I the top of tower 2 to the bottom of tower 1 and provided with a pump IS. The amount of stripper gas employedwill be that determined to be sumcient to strip hydrogen chloride from the reaction product intower I at the temperature maintained in this tower. Line I5 is provided with a bleed-oflrline l1 and a makeup line [8.

'In the embodiment shown in Fig. 2 the sequence When the apparatus is employed for the reaction between two gases of diflferent solubility in "a selected liquid, the more soluble gas is introtroduced through line 301 In this case the "liqof operations is carried out in a single tower (165'.-

ignated by numeral l9. This tower is divided into zones by partitions 20. The upermost zone is theabso'rption zone 2|, packed in the manner referred to with respect to tower 2. The next lower zone is the reaction zone 22, packed the same as reaction vessell, Fig. l, and provided at its bottom with a perforated ring or other distributing device 23,.to which gaseous hydrogen chloride is fed byline 24. The lowermost zone 25 is provided with a heater 26, is suitably packed in the same manner as zone. 2|, and is provided near its bottom'with a perforated ring orother distributing device 21, to which stripping gas is fed by line 28, which is also connected to the top of zone 2|. Line '28 is provided witha draw-oil line 29 from which gas may be bled uid medium is recycled back to line 30, provision being made for the separation of the reaction product therefrom where the reaction product is aliquid. e

'The nature and objects of the present invention having been fully described andjillustrated, what I desire to claim as new and useful and to secure by Letters Patent is:

1. In the isomerization of a normal paraflin hydrocarbon to an iso-paraflin in the presence of a catalyst and a gaseous promoter, the steps off from time to time as required. The hydrocarbon feed is introduced into the top of zone 2| by line 30 and the hydrocarbon productis withdrawn from the bottom of zone 25 by line 3|.

It will be understood that temperature controlling coils may also be utilized in zones 2i and 22 if required. Makeup gas may be introduced into the system by way of line 32.

action between a liquid anda gas, such, for example, as chlorination, the liquid tobe chlorinated is introduced by way of line 30 and the chlorine is introduced by way of line 24. When a stripper gas is employed it will be introduced through line 28. -It will be understood that, as in the case of the apparatus sho in Fig. 1, the provisions for the use or a stripper gas may be omitted. I

carbon feed into the upper portion of the absorption zone and passing it in sequence through the three zones from the top to the bottom of each, introducing the gaseous promoter into the bottom of the reaction zone and maintaining gas.

flow from the top oi the desorption zone to the bottom of the reaction zone and from thetop of the reaction zone to the bottom of the absorp-'- tion zone.

2. A process according to claim 1 in which a circulation of stripper gas difierent from the promoter gas is maintained through the system upwardly through each of the zones in sequence 

